1. Field of the Invention
This invention relates generally to an operating mechanism for moving fastening elements of a closure such as a window, shutter or door simultaneously in opposite directions. The fastening elements, e.g. espagnolette bars, are provided at a frame member at one edge of the panel, and are required to be moved simultaneously in directions opposite to one another. Particularly, the invention relates to an operating mechanism interconnecting such fastening elements so that they are caused to undergo such opposite movement.
2. Review of the Prior Art
There have been many proposals hitherto for mechanisms for causing such opposite movement of two fastening elements such as espagnolette bars; for example, rack and pinion mechanisms wherein members connected to two espagnolette bars have rack formations and pinion is provided therebetween engaging both racks so that the members move together in opposite directions. A manually operable handle could be connected to the pinion. One problem in the design of such operating mechanisms is that they are generally bulky and difficult to accommodate in relation to a window frame member of modern extruded metal or plastics type, which is designed to be as slim and unobtrusive as possible.
To accommodate such a rack and pinion mechanism in a frame member would require the parts to be of very small size, and in particular the reduction in diameter of the pinion to the extent necessary would mean that it may not engage properly with the rack members.